— The historic space shuttle gantries that for decades stood at Launch Pad 39B at NASA's Kennedy Space Center, Fla., are no more. After more than two years of careful "deconstruction" work, demolition crews told NASA on Wednesday (Sept. 14) that the pad was "clean" of the fixed and rotating service structures that supported the launch of 53 shuttle missions.

Started in 2009 in support of NASA's now-canceled Constellation program and its Ares rockets, work to clear the towers was focused on converting 39B to a "clean pad," capable of launching different types of crewed and uncrewed boosters. The pad may now be leased by NASA to companies providing commercial rockets to fly astronauts to the International Space Station (ISS). Or, together with its yet-to-be-cleaned twin pad 39A, Pad 39B could also be used to support NASA's recently revealed Space Launch System heavy-lift launch vehicle.

Future rockets launching from Pad 39B will arrive with their own mobile gantries, similar to how the pad got its start more than 40 years ago.

First used to launch the Apollo 10 mission on a Saturn V rocket in May 1969, Pad 39B was augmented for the space shuttle program with a 267-foot fixed service structure (FSS) assembled in part from one of the mobile launchers that supported the earlier moon-bound flights.

A 130-foot-high-by-102-foot-long rotating service structure (RSS) was also erected to protect the shuttle orbiters from the elements and provide access to their cargo bays.

Together, 39B's FSS and RSS towers supported two decades of shuttle launches. The gantries' first shuttle launch was the ill-fated Jan. 28, 1986 STS-51L mission, which ended 73 seconds into flight with the tragic loss of Challenger and its crew. Fifty-two missions later, Discovery's STS-116 crew became the last to cross the FSS's orbiter access arm and launch on a shuttle from 39B on Dec. 9, 2006.

One more rocket lifted off Pad 39B before the towers were removed. NASA's Ares I-X unmanned test flight lifted off on Oct. 28, 2009, after new lightning protection towers were erected around the pad and two of the FSS's access arms had been detached, lowered and removed.

NASA paid $1.3 million to LVI Environmental Services of New York to remove the historic towers piece-by-piece to avoid damaging the concrete pad foundation. Per LVI's contract with the space agency, the gantries' scrap metal was recycled.

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Launch Pad 39B at NASA's Kennedy Space Center, Fla., as seen in December 2007, a year after the pad's final space shuttle launch but before the fixed (at center) and rotating (at left) service structures began being dismantled. The mobile launch platform to the right was moved by crawler transporter off the pad and back to the Vehicle Assembly Building three miles away.

Photo: collectSPACE

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Apollo 10's May 18, 1969 liftoff to the moon marked the first launch from Pad 39B. The red umbilical tower was later converted to build the pad's fixed service structure (FSS). In addition to Apollo 10's Saturn V, Pad 39B also supported the launch of the three Saturn IB rockets (three Skylab crews and the Apollo-Soyuz Test Project). The launch umbilical tower that later became Pad 39B's FSS was used for Apollo 10 on 39B and Apollos 13, 15, 16, and 17 on Pad 39A.

Photo: NASA

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The fixed and rotating service structures at Pad 39B supported 54 launches between 1986 and 2009. Space shuttle Challenger's ill-fated STS-51L launch was the first to use the towers. NASA's Ares I-X test flight was the last.

The first piece of Pad 39B to be removed, the 80-foot lightning mast that topped the fixed service structure (FSS), was lowered on March 3, 2009. NASA's first launch pad lightning protection mast, it was used for the 1975 Apollo-Soyuz Test Project (ASTP) before being adapted for the space shuttle program.

Photo: NASA/Amanda Diller

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On June 3, 2009, the oxygen vent hood — the "beanie cap" — and gaseous oxygen vent arm were removed from 39B's fixed service structure (FSS) and lowered the 227 feet to the ground. The beanie cap prevented vapors escaping from the top of the shuttle's external fuel tank from condensing into ice that could dislodge and damage the orbiter during launch.

Photo: NASA/Jim Grossmann

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On June 20, 2009, the orbiter access arm and its "white room" was removed from Pad 39B's fixed service structure and lowered the 147 feet to the ground. The orbiter access arm allowed personnel — including 53 astronaut crews — to enter the shuttle's crew cabin. The environmental chamber at the arm's end, the "white room," mated with the orbiter's crew hatch.

Both the gaseous oxygen vent arm with its "beanie cap" and orbiter access arm with its "white room" will eventually go on display at the Kennedy Space Center Visitor Complex alongside space shuttle Atlantis.

Photo: NASA/Kim Shiflett

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Construction crews began dismantling 39B's rotating service structure (RSS) in September 2010. To avoid damaging the pad's concrete surface, sand, reinforcing steel and large wooden mats were put down under the RSS before workers tore into the tower using a hydraulic shearer.

Photos: NASA/Jim Grossmann

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One month after workers began dismantling the rotating service structure, the base of the tower — the levels used to service the space shuttle orbital maneuvering system (OMS) pods — had been torn down.

Photo: NASA/Jack Pfaller

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Rubble from the rotating service structure (RSS), as seen on Oct. 22, 2010. NASA's contract with LVI Environmental Services of New York included trucking away the refuse and recycling or disposing of the debris.

Photo: NASA/Jack Pfaller

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Construction crews began on March 21, 2011 dismantling Pad 39B's Fixed Service Structure (FSS). Using large cranes, each of the FSS's 12 levels were removed, floor-by-floor.

Photo: NASA/Frankie Martin

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The fixed service structure was the pad's most prominent feature, standing 347 feet from ground level to the tip of the lightning mast. Its 12 floors were positioned at 20-foot intervals with the first located 27 feet above the pad surface.

Photos: NASA/Kim Shiflett

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The fixed service structure's eighth floor was removed by large crane on April 6, 2011.

Photo: NASA/Kim Shiflett

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By the end of April 2011, the fixed service structure stood shorter than the rotating service structure.

Photo: collectSPACE

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Using a hydraulic shearer, construction crews tore into the major feature of the rotating service structure, the payload changeout room (PCR). An enclosed, environmentally controlled area that supported payload delivery and servicing at the pad, the PCR mated to the orbiter cargo bay for vertical payload installation.

Photo: collectSPACE

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By May 18, 2011, the rotating service structure had been reduced to just its frame.

Photo: NASA/Jim Grossmann

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In June 2011, workers began using a large crane to dismantle the final sections of the RSS.

Photo: NASA/Jim Grossmann

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Work dismantling the rotating service structure was completed in June 2011, leaving just the final levels of the fixed tower to be removed.

Photo: NASA/Jim Grossmann

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Workers used a crane on June 9, 2011, to remove the rotating service structure's access arm section.

Photo: NASA/Cory Huston

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By the beginning of August 2011, only the launch pedestals that supported the mobile launch platform remained at Launch Pad 39B following the deconstruction of the towers. Only the cleanup of the sand, reinforcing steel and large wooden mats that were placed over the pad's concrete surfaces to protect them remained to be done.

Photo: NASA/Kim Shiflett

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The deconstruction of Pad 39B was declared completed on Sept. 15, 2011. The only remnants of the towers still remaining at the pad are the support hardware for the mobile launch platforms. The water tower at right was used for sound suppression during launches.

Photo: NASA/Jim Grossmann

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Three 600-foot-tall lightning protection towers still surround Pad 39B. Erected prior to the Ares I-X test flight in October 2009, they replaced the need for the 80-foot lightning mast that stood atop the now-removed fixed service structure.

Photo: NASA/Jim Grossmann

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Viewed from the two-track crawlerway, the now "clean" Pad 39B stands ready and waiting for the next generation of rockets that will depart Earth for space from its concrete surface.